Problem: Which of the following numbers is a multiple of 3? ${49,63,67,70,112}$
Answer: The multiples of $3$ are $3$ $6$ $9$ $12$ ..... In general, any number that leaves no remainder when divided by $3$ is considered a multiple of $3$ We can start by dividing each of our answer choices by $3$ $49 \div 3 = 16\text{ R }1$ $63 \div 3 = 21$ $67 \div 3 = 22\text{ R }1$ $70 \div 3 = 23\text{ R }1$ $112 \div 3 = 37\text{ R }1$ The only answer choice that leaves no remainder after the division is $63$ $ 21$ $3$ $63$ We can check our answer by looking at the prime factorization of both numbers. Notice that the prime factors of $3$ are contained within the prime factors of $63$ $63 = 3\times3\times7 3 = 3$ Therefore the only multiple of $3$ out of our choices is $63$. We can say that $63$ is divisible by $3$.